Search Results (23)

In order to validate the applicability of pXRF for rapid in situ detection of heavy metals in urban soils and to accurately obtain an assessment of soil quality in Changchun, a city in northeast China, 164 soil samples from within the main urban area of Changchun were collected for pXRF analysis. The main stable elements Si and Ti were used to establish a matrix effect correction model, and the values of Cr (64.2 mg⋅kg⁻¹), Cu (43.8 mg⋅kg⁻¹), Zn (96.2 mg⋅kg⁻¹), As (20.9 mg⋅kg⁻¹), and Pb (57.4 mg⋅kg⁻¹) were predicted. The empirical findings indicate that the quality of soil data from the pXRF was improved to different degrees under the correction model, and it became a relatively reliable dataset; the order of improvement was Cu > Pb > Cr > Zn > As. A comprehensive assessment indicated that Changchun City is primarily contaminated by the heavy metals As, Pb, and Cu, with the main sources being automobile manufacturing and pharmaceutical chemical production. These findings align with previous studies and have produced favorable outcomes in practical applications. This rapid, non-destructive and economical detection method is very applicable and economical for the sustainable monitoring and control of heavy metals in large cities. This study provides a basis for rapid large-scale prediction of urban soil safety and protection of local human health. Full article

The concept of high-quality development (HQD) is characterized by its emphasis on efficiency, equity, and environmental sustainability. In the context of China’s new urbanization development, the metropolitan area plays a crucial role in facilitating and sustaining HQD. This study focuses on the Changchun Metropolitan Area (CCMA) as a case study to measure the efficiency of high-quality development (HQDE) at the county level using the super-efficiency SBM model and spatial autocorrelation model. Additionally, we examine the spatio-temporal distribution characteristics of HQDE in terms of economy, innovation, coordination, greenness, openness, and sharing (EICGOS). The main findings are as follows: (1) The HQDE of the CCMA ranges from 0.7 to 0.8 with an initial rapid increase followed by a gradual decline; however, there are notable variations among different counties. (2) Regarding spatial structure within the metropolitan area, highest efficiency is observed in the half-hour living circle followed by the 2-h accessibility circle while lowest efficiency is found in the 1-h commuting circle. Over time, there is a declining trend in efficiency within core leading areas. (3) In terms of dimensions, CCMA demonstrates the highest level of economic development efficiency (EDE), whereas green development efficiency (GDE) exhibits lower levels compared to other dimensions. Furthermore, development efficiencies across all dimensions show a decline over time. (4) Spatially distributed patterns reveal significant agglomeration areas for HQDE within the CCMA region. High-high agglomeration areas are predominantly concentrated in the central region of Changchun and southern region of Liaoyuan while low-low agglomeration areas primarily exist in northwest Songyuan and specific counties within Changchun. To attain HQD of the CCMA, it is advisable to bolster the economic scale of the central city, mitigate developmental disparities between counties and cities, and expedite green transformations in old industrial cities. These findings offer a valuable point of reference for optimizing resource allocation at the metropolitan level and devising strategies to foster regional HQD. Full article

Using the Urban Network Analysis Tool, the centrality of a road network (closeness centrality, betweenness centrality, and straightness centrality) was calculated, and the POI data of the commercial facilities were reclassified. KDE estimation was used to estimate the centrality of the traffic network, and the correlation coefficient was calculated to explore the spatial relationship between road network centrality and the types of commercial facilities (catering facilities, shopping facilities, residential life facilities, and financial and insurance facilities). The results indicate the following: (1) Closeness centrality displays a discernible “Core–Periphery” pattern, and the high-value areas of betweenness centrality are mainly concentrated around the main arterial roads of the city. In contrast, straightness centrality unveils a polycentric structure. (2) The spatial distribution of commercial facilities demonstrates a notable correlation with the centrality of the road network. From the perspective of centrality, the distribution of residential life facilities is most strongly influenced by road network centrality, followed by financial and insurance facilities and then catering facilities, with the distribution of shopping facilities being the least affected. (3) The centrality of the road network plays a crucial role in shaping the arrangement of commercial facilities. Closeness centrality significantly influences the distribution of residential life facilities, catering facilities, and shopping facilities. Betweenness centrality has a noteworthy impact on the selection of locations for financial and insurance facilities, as well as residential life facilities. Furthermore, areas characterized by better straightness centrality are preferred for the distribution of residential life facilities, financial and insurance facilities, and catering facilities. (4) The centrality of the road network has a greater influence on the arrangement of various commercial facilities than the population distribution. Full article

Nighttime light (NTL) data and points of interest (POI) data offer precise visual indications of the distributional characteristics of urban spatial structures. This study employed nighttime light data and point of interest data to investigate spatial distribution patterns in Changchun, a selected study area. The built-up area was extracted from the nighttime light data, while kernel density analysis was utilized to examine the distribution of point of interest data. The processing outcomes of both datasets were gridded with spatially resolved resolution. Afterward, the fishnet tool was employed to conduct two-factor integrated mapping and visual analysis, which helped identify shared or divergent spatial coupling relationships. The results indicated a high degree of consistency in the distribution of both NTL and POI across Changchun, with 84.58% of the coupling demonstrating a concordant pattern. The spatial analysis conducted in this study showed that the heterogeneities of the coupling relationship within each administrative borough expanded outward from the center of the borough. POI provided a more accurate depiction of the spatial distribution of urban built-up areas compared to NTL, leading to a more precise representation of spatial patterns of human activity intensity. Changchun has undergone zoning adjustments, resulting in the emergence of multiple urban centers in both the central city and the surrounding administrative districts. These urban centers are gradually merging into each other. The study found that the level of spatial coupling was much higher in the central area compared to the surrounding administrative districts. This has contributed to the formation of multiple urban centers and the gradual expansion of the urban built-up area beyond the main city, indicating a trend towards regional integration and development. This study provides a more detailed and accurate description of the current distribution of urbanization and spatial structural characteristics of Changchun by investigating the spatial coupling between POI and NTL. The findings contribute to a better understanding of the urban development patterns in the region and provide insights for future urban planning and management. Full article

Mercury is a global pollutant that has attracted widespread attention due to its persistence, concealment, and ease of migration. As the main setting for human production and life, urban ecosystems play significant roles in the global mercury cycle. Urban vegetation also plays an important role in regional mercury cycles. In this study, several common tree species in the green vegetation of Changchun were used as research objects to examine the mercury pollution characteristics of leaf litter and the surrounding soil. In this investigation, 100 sampling sites were set up in Changchun City to collect leaf litter and the surrounding topsoil. An RA-915⁺ Hg analyzer was used to determine the total mercury concentration levels. The results showed that content levels of mercury in plants ranged between 0.0133 and 0.1945 mg/kg, and different species displayed varying levels of mercury accumulation. For example, the content of mercury in Pyrus ussuriensis Maxim. was found to be 0.0755 mg/kg higher than that in the other examined subjects. It was also determined that the plant mercury concentration levels were the highest in the older industrial zones, while the lowest mercury levels were found in the new economic development zones. Furthermore, the plant mercury levels of the roadside areas were higher due to vehicle pollution discharge. Regarding the mercury pollution levels of the surface-layer soil, the soil of old industrial zones’ surface layers had higher levels of mercury pollution than the other tested sites. However, no notable connection was observed between the mercury concentration levels of the vegetation and those of the soil. This study’s results revealed that the mercury pollution of plants in Changchun City is not severe. The mercury levels in the industrial zones were graded as moderate, and those in the other regions were graded as low. Full article

As a susceptible demographic, elderly individuals are more prone to risks during sudden disasters. With the exacerbation of aging, new challenges arise for urban disaster reduction and prevention. To address this, the key is to establish a community-scale resilience assessment framework based on the aging background and to summarize factors that influence the resilience level of communities. This approach is a crucial step towards seeking urban disaster prevention and reduction from the bottom up, and serves as an important link to enhance the capacity of urban disaster reduction. This paper explores community resilience evaluation indicators under the background of aging, builds a community resilience evaluation index system based on the Pressure–State–Response, uses the entropy weight method to weigh the indicators, and carries out a resilience evaluation of 507 communities in the main urban area of Changchun. The empirical results indicate significant spatial differentiation of community resilience in the main urban area of Changchun. Moreover, the regional development is unbalanced, showing a spatial distribution pattern of weakness in the middle and strength in the periphery. The ring road network highlights the difference between the new and old urban areas. The high contribution indexes of community resilience in the main urban area of Changchun were concentrated on disaster relief materials input, community self-rescue ability, and disaster cognition ability. Finally, strategies to improve community resilience are proposed from the perspectives of stress, state, and response, emphasizing community residents’ participation, conducting disaster prevention and reduction training, and improving community response-ability. Full article

With the rapid development of China’s economy, the process of industrialization and urbanization is accelerating, and environmental pollution is becoming more and more serious. The urban agglomerations (UAs) are the fastest growing economy and are also areas with serious air pollution. Based on the monthly mean PM_2.5 concentration data of 20 UAs in China from 2015 to 2019, the spatiotemporal distribution characteristics of PM_2.5 were analyzed in UAs. The effects of natural and social factors on PM_2.5 concentrations in 20 UAs were quantified using the geographic detector. The results showed that (1) most UAs in China showed the most severe pollution in winter and the least in summer. Seasonal differences were most significant in the Central Henan and Central Shanxi UAs. However, the PM_2.5 was highest in March in the central Yunnan UA, and the Harbin-Changchun and mid-southern Liaoning UAs had the highest PM_2.5 in October. (2) The highest PM_2.5 concentrations were located in northern China, with an overall decreasing trend of pollution. Among them, the Beijing-Tianjin-Hebei, central Shanxi, central Henan, and Shandong Peninsula UAs had the highest concentrations of PM_2.5. Although most of the UAs had severe pollution in winter, the central Yunnan, Beibu Gulf, and the West Coast of the Strait UAs had lower PM_2.5 concentrations in winter. These areas are mountainous, have high temperatures, and are subject to land and sea breezes, which makes the pollutants more conducive to diffusion. (3) In most UAs, socioeconomic factors such as social electricity consumption, car ownership, and the use of foreign investment are the main factors affecting PM_2.5 concentration. However, PM_2.5 in Beijing-Tianjin-Hebei and the middle and lower reaches of the Yangtze River are chiefly influenced by natural factors such as temperature and precipitation. Full article

Urban parks are one of the primary settings for older adults to exercise, and their health benefits have been confirmed by a large number of studies. However, with the increased social attention to mental health, there is not enough research on the short-term mental health recovery of older adults in parks. Meanwhile, the health recovery effects of winter parks in special climate areas have not been well explored. This study aimed to explore the effects of winter parks in cold regions on the short-term mental health recovery of older adults and the potential predictors of these effects, including individual status, park characteristics, and behavioral characteristics. This study divided short-term mental health recovery into cognitive recovery and emotional improvement, and selected the digit span test and 10 kinds of emotional expression as the experimental methods, recruited 92 older adults from 6 parks in Changchun, and compared the pre-test and post-test results for evaluation. The results showed that winter parks in cold cities still had short-term cognitive recovery and emotional improvement effects on older adults. The main park characteristic factors affecting the overall cognitive recovery were the evergreen vegetation area and the existence of structures, and that which affected the overall emotional improvement was the main pathway length. Furthermore, individual conditions, including gender, age, physical health, living and customary conditions, and park characteristics, including park type, park area, main pathway length, square area, equipment area, evergreen vegetation area, the presence of water, and structures, all related to short-term mental health recovery effects. Among behavioral characteristics, stay time in parks and MVPA (Moderate and Vigorous Physical Activity) times were also related to certain effects, but behavior type was not. Full article

People-oriented urban planning requires that service facilities should efficiently meet individual and community activity needs across the demographic landscape that defines a city. To develop a conceptual basis for urban spatial infrastructure optimization, we empirically studied existing population activities and service facilities in Changchun, China, using kernel density estimation, bivariate spatial autocorrelation analysis, and other models. The spatial relationships we derived from multiple sources of big data such as mobile phone signaling and POI data indicated that the intensity of population activity has obvious temporal regularity, and its spatial distribution is “center-periphery.” Service facilities display a “One main and two subs” distribution with no obvious spatial dependence between the core’s density and diversity. Population activities and service facility diversity show a high-high spatial correlation and multiple matching patterns. At the same time, a certain degree of spatial mismatch between different age groups and service facilities was also observed. Our research suggests several urban renewal actions to rectify this mismatch, such as: decentralizing the core area medical service facilities; reducing the attractiveness of the core area and its traffic pressure; and renewing and renovating old facilities to reduce construction costs. At a government planning level, construction along the periphery of the urban can enrich the diversity of its service facilities to improve the efficiency of spatial allocation. Full article

Among human activities, coal mining and the combustion of fossil fuels are important sources of mercury in the environment. Research on mercury pollution in coal mining areas and surrounding cities, especially in densely populated areas, has always been at the forefront of this research field. In order to study the characteristics of environmental mercury pollution in small and medium-sized coal mining areas and surrounding towns in China, this study selected the main urban area of Jiutai District, a typical mining town in the Changchun City circle industrial base in northeast China, as the research object. In this study, the geo-accumulation index (I_geo) was used to study the soil mercury pollution degree in Jiutai District, the potential ecological risk index (Er) was used to evaluate the potential ecological risk of soil mercury in the study area, and the human exposure risk assessment model was used to evaluate the non-carcinogenic risk of soil mercury to the human body. The results showed that 32% of the soil samples in the study area had a higher mercury content than the regional soil background value of Jilin Province (0.04 mg·kg⁻¹). According to the I_geo, 19% of the sample sites in the study area were polluted (index > 0). In general, the soil mercury pollution level in Jiutai District is low, and the polluted areas are mainly concentrated in the northeast of the study area. The Er of the soil mercury in the study area ranged from 7.2 to 522.0, with 32% of the sampling sites having a moderate or above potential ecological risk (Er > 40), and the potential ecological risk level of the soil mercury was higher in the northeast of the study area. The non-carcinogenic risk index (HQ) and total non-carcinogenic risk value (HI) of the soil mercury were all far less than 1, indicating that soil mercury pollution in the study area did not harm the health of local adults. The oral ingestion of soil mercury is the main form of human exposure to mercury. Full article

Urban waterlogging will harm economic development and people’s life safety; however, the waterlogging risk zoning map provides the necessary decision support for the management of urban waterlogging, urban development and urban planning. This paper proposes an urban waterlogging risk assessment method that combines multi-criteria decision analysis (MCDA) with a geographic information system (GIS). The framework of urban waterlogging risk assessment includes four main elements: hazard, exposure, vulnerability, and emergency response and recovery capability. Therefore, we selected the urban area of Changchun City, Jilin Province as the study area. The Analytic Hierarchy Process (AHP) is a generally accepted MCDA method, it is used to calculate the weight and generate a result map of hazards, exposure, vulnerability, and emergency responses and recovery capability. Based to the principle of natural disaster risk formation, a total of 18 parameters, including spatial data and attribute data, were collected in this study. The model results are compared with the recorded waterlogging points, and the results show that the model is more reliable. Full article

With the rapid development of economy and urbanization acceleration, ozone (O₃) pollution has become the main factor of urban air pollution in China after particulate matter. In this study, 90th percentile of maximum daily average (MDA) 8 h O₃ (O₃-8h-90per) and PM_2.5 data from the Tracking Air Pollution in China (TAP) dataset were used to determine the mean annual, seasonal, monthly, and interannual distribution of O₃-8h-90per and PM_2.5 concentrations in Northeast China (NEC). The O₃-8h-90per concentration was highest in Liaoning (>100 μg/m³), whereas the highest PM_2.5 concentration was observed mainly in urban areas of central Liaoning and the Harbin–Changchun urban agglomeration (approximately 60 μg/m³). The O₃-8h-90per concentrations were highest in spring and summer due to more intense solar radiation. On the contrary, the PM_2.5 concentration increased considerably in winter influenced by anthropogenic activities. In May and June, the highest monthly mean O₃-8h-90per concentrations were observed in central and western Liaoning, about 170–180 μg/m³, while the PM_2.5 concentrations were the highest in January, February, and December, approximately 100 μg/m³. The annual mean O₃-8h-90per concentration in NEC showed an increasing trend, while the PM_2.5 concentration exhibited an annual decline. By 2020, the annual mean O₃-8h-90per concentration in southern Liaoning had increased considerably, reaching 120–130 μg/m³. From the perspective of city levels, PM_2.5 and O₃-8h-90per also showed an opposite variation trend in the 35 cities of NEC. The reduced tropospheric NO₂ column is consistent with the decreasing trend of the interannual PM_2.5, while the increased surface temperature could be the main meteorological factor affecting the O₃-8h-90per concentration in NEC. The results of this study enable a comprehensive understanding of the regional and climatological O₃-8h-90per and PM_2.5 distribution at distinct spatial and temporal scales in NEC. Full article

The mercury that is released from the centralized treatment of municipal solid waste is an important source of atmospheric mercury. We chose the main urban area of Changchun as a representative area. Environmental factors such as total mercury content, temperature, wind speed, and other factors were measured in samples from the trash cans of two types of collection points (trash cans and garbage stations), the topsoil under the selected trash cans, and the ambient air above the selected trash cans. The potential ecological risks of mercury pollution were evaluated. The results showed that the mercury content levels of all sample types in the refuse transfer station were higher than the garbage cans and there were no significant differences observed between soil surface mercury and garbage cans. The mercury content levels in the atmosphere and the surface soil at the garbage collection points were found to increase along the cascade relationship of the garbage collection. However, there were no correlations observed between the atmospheric mercury content levels and the surface soil mercury content levels with the attachments and the sum of the former two. There were no correlations observed between surface soil and the attachments, or among the attachments, surface soil, and the atmospheric mercury content levels. The mercury content levels in the attachments, surface soil, and atmosphere of the garbage collection points in the study area were negatively correlated with the loop lines. Meanwhile, the potential ecological risk indexes of the garbage cans and garbage stations were found to be high. The chronic non-carcinogenic risks of mercury to children and adults were determined to be very low. The risks of mercury to children were higher when compared with adults. The highest non-carcinogenic risks of mercury pollution were determined to be within the central area of Changchun. Full article

China has clearly put forward the strategic goals of reaching the “Carbon Emission Peak” by 2030, and achieving “Carbon Neutrality” by 2060. To achieve these goals, it is necessary to precisely understand the spatial distribution characteristics of historical carbon emissions in different regions. This paper has selected a representative national-level urban agglomeration in China, the Harbin–Changchun urban agglomeration, to study the temporal and spatial distribution characteristics of carbon emissions in its counties. This paper has constructed global and local Moran’s I indexes for the 103 counties in this urban agglomeration by using the carbon emission values reflected by night light data from 1997 to 2017 to perform global and local autocorrelation analysis on a spatial level. The results show that: (1) the main characteristic of carbon emission clustering in the Harbin–Changchun urban agglomeration is similar clustering; (2) the changes in carbon emissions of the Harbin–Changchun urban agglomeration have a strong correlation with relevant policies. For example, due to the impact of the “Twelfth Five-Year Plan” policies, in 2013, the global county-level Moran’s I index of the carbon emissions in the Harbin–Changchun urban agglomeration decreased by 0.0598; (3) the areas where high carbon emission values cluster together (“High–High Cluster”) and low carbon emission values cluster together (“Low–Low Cluster”) in the Harbin–Changchun urban agglomeration are highly concentrated, and the clusters are closely related to the development level of different regions. Full article

Economic development and ecological restoration guided by policies has had a profound impact on the relationship between ecosystem service supply and consumption in the past few decades. Exploring the relationship in specific study areas is necessary to support regional planning for sustainability. In this study, we analyzed the equilibrium relationship between ecosystem service supply and consumption driven by economic development and ecological restoration from 1995 to 2018 in Northeast China. We quantified the supply and consumption of three critical ecosystem services, food production, water yield and atmospheric regulation, and identified the main areas for supply and consumption of ecosystem services. We measured the quantity and spatial equilibrium relationship between ecosystem service supply and consumption driven by economic development and ecological restoration at economic megaregion scale. We found the new industrial structure shaped by regional economic development policies formed the new ecosystem service consumer demand. The development of agricultural industry not only resulted in the increase of water consumption, but also the scope of water consumption was expanded in Northeast China. The development of tertiary industry causes the change of atmospheric regulation consumption in urban agglomeration. What’s more, economic development exacerbated imbalances in the supply and consumption of ecosystem services. The unbalanced areas where food supply was less than consumption were in the clusters of Harbin, Changchun, Shenyang, and coastal cities. Since food products can circulate freely through the market, this imbalance will not fundamentally affect regional food security, but will improve the level of agricultural industrialization and scale. The implementation of the grain economic policy caused the rapid expansion of unbalanced areas where water supply was less than consumption. The incredible space mismatch between the supply and consumption of ecosystem services still exists for a long time. However, the implementation of the ecological restoration didn’t effectively solve the problem of insatiable ecosystem service consumption. The ecosystem service consumption brought by economic development need to be given the utmost attention when formulating ecological restoration policies and economic development policies. The results can provide insights for enhancing economic sustainability in northeast china, as well other economic megaregion with similar characteristics throughout the world. Full article